Gas File: PROGRAM STOPPED TOO MANY PRIMARIES IPRIM

Garfield++
1

I am facing the situation first documented here in this issue: GarField++ Gas File Error: “PROGRAM STOPPED TOO MANY PRIMARIES IPRIM” (I am a new user and so can’t put links in posts)

It exits with the following error:

  MEAN ELECTRON ENERGY =   0.0369 EV. ERROR =  +-    0.08%


  SOLUTION FOR STEADY STATE TOWNSEND PARAMETERS
  -------------------------------------------------

 SPACE STEP BETWEEN SAMPLING PLANES = 0.40843D-03 MICRONS.

   PROGRAM STOPPED TOO MANY PRIMARIES IPRIM=*******

This is when running the file garfieldpp/Examples/Paschen/gastable.C, with the only modification being that I change the gas to pure SF6.

Following the suggestion in the above post to lower the lower bound of the electric field does not work: I’ve gone as low as 1 eV/cm.

Does anyone have any additional tips? @Khalil_Alashy did you ever get this resolved?

Thanks!

2

Hi,

at what electric field does this happen?

3

It happens at all field values I have tried, including 0.1, 1, 10, 100, and 1000 kV/cm

4

For reference, this was reported earlier by @Khalil_Alashy in this post

5

Hi,

at 100 kV/cm and 1000 kV/cm, Magboltz seems to run ok for me, but at 1 kV/cm and 10 kV/cm it stops indeed with the same error message that you got.

At these fields the attachment rate is extremely large: from the output of Magboltz (the first part, before running the steady-state Townsend simulation) I got η ~ 3 × 108 / cm at 1 kV/cm, η ~ 2 × 106 / cm at 10 kV / cm. This means that the electron becomes attached before it can drift a significant distance, so the swarm parameters are not really meaningful…

At what electric field do you actually operate your detector?

6

Thanks everyone for the input. Indeed, the electric field values were too low and that was the issue. When I increase them to larger values, the program seems to run as expected.

I am not running a detector, just doing some simulations of breakdowns of different gases.